“Ready for a little science, squirt?” Mirko’s voice echoed in the deserted plaza, charged with an energy that seemed to make the air vibrate. “I need a boost. A good one. I wanna see if I can break the sound barrier in a hundred-meter dash.”

Yu Takeyama crossed her arms, her expression a perfect mix of disbelief and exhaustion. “Excuse me? Did you just ask a minor to give you a ‘boost’ like you’re in some dark alley?”

“Oh, come on, Takeyama! Don’t be so uptight,” Mirko retorted, bouncing lightly on the balls of her feet. “You know what I mean.”

“Let me see if I understand,” Yu said, ignoring the rabbit hero’s enthusiasm and turning her gaze to Izuku, who was caught between the two. “You and I drafted an agreement. We wrote it on the back of a napkin from a ramen stand—a legally questionable document at best—which clearly specifies that today’s research would focus on ‘thermal conductivity’ and ‘hard impact’.”

Izuku nodded, his face the very picture of professional seriousness. “The terms were unequivocal. Item 3.a: Analysis of heat dissipation in a gigantified state. Item 3.b: Measurement of impact force in a controlled fall.”

“Exactly. Unequivocal terms,” Yu continued, shooting a death glare at Mirko. “And yet, the first thing you do when you get here isn’t to prepare for a scientific analysis, but to demand a speed enhancement so you can play race car driver through an empty city.”

Mirko paused mid-stretch—a series of movements that seemed to defy human anatomy—and gave her a shameless grin. “Warming up is the most important part of any workout, Takeyama! I need to get the blood flowing, get the muscles ready. How do you expect science to progress if I don’t prepare properly?”

“And does that preparation necessarily involve running up the sides of buildings?” Yu asked with palpable sarcasm.

“Of course it does! It’s to test the limits,” Mirko argued, now holding a finger in the air with a lecturing gesture. “We can’t just jump into evaluating your… conductivity, without a proper preliminary phase. That would be incredibly unprofessional.”

“What’s unprofessional is using Japan’s most advanced training facility as your personal racetrack,” Yu shot back, pinching the bridge of her nose.

“Bah! Less talk, more action,” Mirko said, dismissing her complaints with a wave of her hand. She turned to Izuku, her red eyes shining with an almost childlike energy that contradicted her reputation as a fierce hero. “Come on, squirt. Don’t listen to her. Juice me up. I wanna see if I can run up the face of the Central Office Building without losing momentum. I bet I can do it in under ten seconds! What do you say? Ten seconds?”

Izuku looked to Yu for some kind of support, but she just rolled her eyes and sighed, a gesture of total resignation that said, “just do it and get it over with.” She knew it was a lost battle. Letting the rabbit loose first was the only way to get some peace for her own humiliating “science” session.

“Alright, Mirko-san,” Izuku said. “Starting position, please.”

Mirko’s grin widened, an expression of pure, predatory joy. She crouched down at an imaginary starting line, her muscles tensed, ready for the explosion of speed. Izuku walked over and placed his hands on her shoulders. Yu watched from a safe distance. The subtle green energy of Izuku’s Quirk enveloped the hero for an instant.

“Now,” he said.

With a cry of pure euphoria that tore through the silence, Mirko vanished, leaving behind a wake of wind that kicked up dust and a sonic boom that rattled the windows of the nearby buildings. Yu had to shield her face with her arm. She saw a white blur ascending the wall of a skyscraper, defying gravity, before disappearing over the other side of the roof.

A momentary silence fell, broken a couple of seconds later by a series of distant BOOMS that began to echo through the fake city, each followed by a faintly audible cry of joy.

“Well,” Izuku said, looking in the direction she had disappeared. “That should keep her busy for a while.”

He turned to Yu, and his expression changed completely. The amusement vanished, replaced by the intense focus of a researcher on the verge of a breakthrough.

“Your turn,” he said, and the simplicity of those two words sent a chill down Yu’s spine.

“Remember the contract, Izuku,” she said quickly, raising a finger. “Just conductivity and impact today. No weird experiments. No ‘let’s see what happens if…'”

“Before the ‘thermal conductivity’,” he interrupted, his green eyes shining with an idea. “I want to test a theory. One that occurred to me last night after analyzing the data from the experiment with Midnight-sensei.”

Izuku began to circle her, observing.

“With Nemuri, the breakthrough wasn’t adding power,” he explained, gesturing as he spoke. “It was changing the nature of its application. Her Quirk is ethereal; its natural state is to expand, to disperse. It always wants to occupy more space. What we did was force it to do the exact opposite. We compressed it until that entire cloud became a single drop of liquid.”

He stopped right in front of her, his gaze so intense that Yu felt the urge to take a step back. “Your Quirk, Yu. It’s called ‘Gigantification.’ The name itself implies a single direction: to grow. Everyone, including you, assumes that’s its only function. But… what if the name is wrong? What if it’s an incomplete description?”

“What do you mean, it’s wrong?” she asked defensively. “It’s pretty descriptive. It’s what I do. I get big. End of story.”

“You expand,” he corrected. “That’s the fundamental action. You push your mass and energy outward, increasing your volume. But every fundamental equation in physics, in nature, has its opposite. Every action has an equal and opposite reaction. Expansion has…”

A terrible feeling began to form in the pit of Yu’s stomach. “Compression,” she finished, the word escaping her lips, heavy with a bad feeling. “Shrinking.”

“Exactly,” Izuku said, his face lit up with the thrill of discovery. “What if your real power isn’t just ‘growing’? What if your Quirk is actually ‘Absolute Size Control’? Growing is just half the story. It’s the easy half, the flashy one, the one that manifests naturally. But the other half, compression… could be much, much more interesting.”

Yu stared at him, completely bewildered. Then she shook her head in a firm, emphatic no.

“You’re insane. Absolutely, completely insane,” she declared. “Izuku, I’ve spent thousands, tens of thousands of hours, learning to control it, feeling it, living with it. If I could shrink, if there were even the slightest possibility, don’t you think I’d know? Don’t you think at some point, by accident, I would have felt it?”

“But have you ever actually tried?” he asked, with a simplicity that disarmed all her logic. “Have you ever actively focused on doing the opposite?”

“No! Of course not! Why would I?” she exclaimed in frustration. “My Quirk is called Gigantification! It’s in the damn name! That’s like asking Endeavor to try shooting ice! It goes against his very nature!”

“You’ve never tried because you never thought it was possible,” he insisted. “Every time you activate your power, your intention is to ‘grow.’ Your mind, your instincts, your entire being pushes in that direction. You never had a reason to push the other way. And you never had someone to help you focus your power in a completely new way. Let me be that help, Yu. Just trust me, like Nemuri did.”

She stared at him, a silent war raging inside her. Her skepticism, forged by a lifetime of practical experience, battled against the undeniable evidence of what this kid had accomplished. He had turned Mirko into a living missile and transformed Nemuri’s Quirk. This boy didn’t see things like everyone else. He saw the hidden potential beneath the surface. It was a terrifying, and to her own surprise, strangely tempting prospect.

With a sigh that seemed to carry away all her resistance, she gave in. “Fine. Okay. But if you break me, or I turn into a formless puddle of biological matter, I swear, Izuku, my ghost will haunt you for the rest of your life. I’ll be the most annoying specter you’ve ever met.”

A radiant smile lit up Izuku’s face. “You won’t regret it! Okay, let’s start! Get big! Twenty meters should be enough for the initial test.”

Yu closed her eyes and activated her power. The familiar sensation of growing, of the world shrinking at her feet as she towered over it, filled her with a comforting confidence. This was her element.

“Perfect!” Izuku’s voice came through the small communicator in her ear. She saw his tiny figure run to her foot, which was now the size of a small car. He placed both hands on her ankle, and she felt the slight contact.

“Alright. Now, listen carefully. Forget the word ‘shrink.’ It doesn’t exist in your vocabulary right now. I want you to focus on the sensation of your body. Feel the energy you’re projecting outward to maintain this size. Can you feel it?”

She concentrated. She could feel it.

“Now,” Izuku’s calm voice continued, “I want you to do the opposite. Instead of pushing that energy out… pull it in. Pull everything toward your center. Compress it all!”

The energy of his Quirk flowed into her through his hands. Yu gritted her teeth and focused, fighting against every instinct. It was the strangest, most unnatural feeling she had ever experienced. It wasn’t painful, but it was deeply unsettling. She felt an invisible force crushing her, pulling inward from all sides, a pressure that threatened to fold her in on herself. Vertigo hit her hard, and nausea threatened to rise in her throat. She squeezed her eyes shut, holding on to Izuku’s calm voice and the warm sensation of his power on her ankle.

And then, without warning, something clicked.

She felt like she was falling, but without moving. The ground rushed up to meet her at a dizzying speed. The world around her grew, the buildings soaring like giants. She shot past her normal size in the blink of an eye, a transition so fast she barely registered it, but she didn’t stop. The feeling of compression intensified for a split second until, suddenly, everything stopped.

She landed softly on the cold, rough concrete.

She opened her eyes. The world was gigantic. The cracks in the pavement were massive canyons. A discarded soda can a few feet away was the size of a car. She looked at her own hands. They were tiny, perfectly formed, but the size of a doll’s.

She had done it.

She had done it! A laugh of pure euphoria and amazement bubbled out of her, a high-pitched, tiny sound. She could shrink! The possibilities were endless! Infiltration, stealth, espionage, rescues in tight spaces! A completely new ability! It was revolutionary! It was going to change her entire career!

The euphoria lasted for exactly three seconds.

That’s how long it took for her brain to process two new, terrible sensations. The first was that she was completely surrounded by an immense mountain of purple and ivory fabric. The second was that she felt a decidedly strange breeze in places she had never, ever felt a breeze before.

With a terror that froze the blood in her veins, she looked down.

Her hero costume, designed to stretch to titanic proportions, had returned to its original size.

She, on the other hand, had not.

She was completely, utterly, and minutely naked in the center of a nest made from her own uniform.

Her shriek of panic, a sharp, microscopic squeal, was completely drowned out by a massive BOOM that echoed from the other side of the district, followed by Mirko’s triumphant cry: “AHAHAHA, NEW PERSONAL BEST!”

Izuku, who had been watching the process, saw the giant Yu disappear and a tiny figure appear in her place. His first thought was an exultant, It worked! The hypothesis was correct!

His second thought, as he watched the look of euphoria on the tiny Yu’s face twist into a mask of pure horror, was: Oh, no.

He saw the exact moment she realized her predicament. He saw the panic bloom in her tiny eyes.

Without a word, he took off his jacket. He ran to the pile of fabric, pushing aside the heavy material of Mt. Lady’s costume. Carefully, he wrapped the small, trembling form of Yu in the garment. To her, the jacket was the size of a comforter.

“Don’t look!” Yu’s little voice shrieked, muffled by the fabric. “I told you not to look! You’re a pervert! I knew this was part of your plan!”

“I’m not looking!” he replied. “I can barely see you!”

A tense silence fell, broken only by another distant BOOM, this time a little closer.

“Can you… can you go back to your normal size now?” he asked.

“I DON’T KNOW HOW!” she yelled from inside her shelter. “I JUST LEARNED HOW TO DO THIS, IT DIDN’T COME WITH AN INSTRUCTION MANUAL! AND EVEN IF I KNEW, IF I GROW NOW I’LL STILL BE NAKED, YOU IDIOT! MY COSTUME IS OUT THERE!”

“Right. Flawed logic. My apologies,” he muttered. “Okay… Plan B. Can you… walk? Crawl inside my jacket? We need to hide your uniform.”

There was a struggling sound from within. “THIS JACKET WEIGHS MORE THAN I DO! I CAN’T MOVE! I’M TRAPPED!”

They were at an impasse. An intimate, humiliating, and utterly ridiculous impasse. She, a professional hero capable of stopping giant villains, was now a tiny, naked figure lost in the folds of her teenage assistant’s jacket.

In the distance, another boom, definitely closer, followed by Mirko’s shout: “HEY, GUYS, EVERYTHING ALRIGHT OVER THERE?! I’M GONNA TRY AGAIN, BUT THIS TIME WITHOUT USING MY HANDS!”

Pure panic seized Yu. If Mirko came back and found her like this… death was a preferable option. The total annihilation of the universe was a preferable option.

From inside the dark safety of the jacket, a small hand tugged on the leg of Izuku’s pants. Her voice, when she spoke, was no longer a shout of anger. It was a desperate whisper, devoid of all its strength.

“Izuku… what do we do now?”